JP7313789B2 - sliding parts - Google Patents

Description

The present invention relates to a sliding part that rotates relative to each other, for example, a sliding part used in a shaft sealing device that seals a rotating shaft of a rotary machine in the field of automobiles, general industrial machinery, or other seals, or a sliding part used in bearings of machines in the field of automobiles, general industrial machinery, or other bearings.

2. Description of the Related Art As a shaft sealing device for preventing leakage of a liquid to be sealed, for example, a mechanical seal has a pair of annular sliding parts whose sliding surfaces slide relative to each other. In recent years, it has been desired to reduce the energy lost due to sliding in such mechanical seals for environmental reasons, and positive pressure generating grooves are provided on the sliding surfaces of the sliding parts, which communicate with the outer diameter side, which is the side of the high-pressure sealed liquid, and whose one end is closed on the sliding surface. According to this, when the sliding parts rotate relative to each other, positive pressure is generated in the positive pressure generating grooves to separate the sliding surfaces from each other, and the sealed liquid is introduced into the positive pressure generating grooves from the outer diameter side to retain the sealed liquid, thereby improving lubricity and realizing low friction.

Furthermore, mechanical seals are required to satisfy the condition of "sealing" in addition to "lubricating" in order to maintain sealing performance for a long period of time. For example, the mechanical seal disclosed in Patent Document 1 has a Rayleigh step and a reverse Rayleigh step communicating with the liquid to be sealed in one of the sliding parts. According to this, when the sliding parts rotate relative to each other, positive pressure is generated between the sliding surfaces by the Rayleigh step to separate the sliding surfaces, and the Rayleigh step holds the liquid to be sealed, thereby improving lubricity. On the other hand, in the reverse Rayleigh step, a relatively negative pressure is generated and the reverse Rayleigh step is arranged on the leakage side of the Rayleigh step, so that the high-pressure sealed liquid flowing out between the sliding surfaces from the Rayleigh step can be sucked into the reverse Rayleigh step. In this manner, the liquid to be sealed between the pair of sliding parts is prevented from leaking to the leakage side, thereby improving the sealing performance.

International Publication No. 2012/046749 (pages 14-16, Figure 1)

However, in Patent Document 1, since the sealed liquid is returned to the sealed liquid side in the reverse Rayleigh step, the sealed liquid is not supplied to the leakage side between the sliding surfaces, and there is a risk that a portion that does not contribute to lubricity may be generated. In addition, the liquid to be sealed is likely to leak from the opening of the reverse Rayleigh step, and there is a fear that the lubricity will become poorer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sliding part that supplies a sealed fluid to the leakage side between the sliding surfaces to exhibit high lubricity and less leakage of the sealed fluid.

In order to solve the above problems, the sliding component of the present invention is
An annular sliding component arranged at a relatively rotating portion of a rotating machine,
The sliding surface of the sliding component is provided with a plurality of dynamic pressure generating mechanisms each including a deep groove communicating with the outer diameter side or the inner diameter side and a shallow groove communicating with the deep groove and extending in the circumferential direction.
According to this, since the deep groove portion has a large groove depth and a large volume, a large amount of the sealed fluid supplied to the leak side of the sliding surface can be recovered and returned to the shallow groove portion, and lubricity can be improved by utilizing a wide area extending to the leak side of the sliding surface. In addition, since the deep groove portion is provided with the trap portion, the sealed fluid can be easily held in the deep groove portion, and leakage of the sealed fluid from the deep groove portion can be suppressed.

The deep groove portion may communicate with the outer diameter side.
According to this, since the trap portion is provided in the deep groove portion communicating with the outer diameter side, the sealed fluid is held in the deep groove portion against the centrifugal force generated in the sealed fluid due to the relative rotation of the sliding parts, thereby suppressing the leakage of the sealed fluid from the deep groove portion to the outer diameter side.

The deep groove portion may communicate with the leak side.
According to this, since the trap portion is provided in the deep groove portion communicating with the leak side, leakage of the sealed fluid to the leak side can be suppressed. Furthermore, in the case where the deep groove portion communicates with the outer diameter side, the sealed fluid is held in the deep groove portion against the centrifugal force generated in the sealed fluid due to the relative rotation of the sliding parts and the leakage direction of the sealed fluid, thereby further suppressing the leakage of the sealed fluid from the deep groove portion to the leakage side located on the outer diameter side.

The trap portion may be a trap piece extending from the inner surface of the deep groove portion.
According to this, by extending the trap piece from the inner surface of the deep groove portion, a highly rigid trap portion can be easily formed.

The trap portion may have a guide surface that guides the fluid to be sealed toward the shallow groove portion.
According to this, the sealed fluid held in the deep groove portion by the trap piece can be guided to the shallow groove portion along the guide surface.

The trap portion may be arranged at least nearer to the opening communicating with the leak side of the deep groove portion.
According to this, it is possible to secure the amount of the sealed fluid held in the deep groove.

The trap portion may be arranged at least at an intersection of the deep groove portion and the shallow groove portion.
According to this, the fluid to be sealed moving from the deep groove portion to the shallow groove portion can be held, and the dynamic pressure can be reliably generated.

The trap portions may be arranged line-symmetrically with respect to a center line extending in the radial direction of the deep groove portion.
According to this, it is possible to exhibit the function of retaining the sealed fluid corresponding to the sliding parts that rotate in both circumferential directions.

The trap portion may be molded integrally with a base material that constitutes the sliding surface.
According to this, the trap portion can be easily formed.

The trap portion may form a meandering groove meandering in the deep groove portion.
According to this, the meandering groove can enhance the function of retaining the sealed fluid.

The shallow groove portion of the sliding component according to the present invention extends in the circumferential direction, as long as the shallow groove portion extends with at least a component in the circumferential direction. The deep groove portion extending in the radial direction means that the deep groove portion extends with at least a component in the radial direction, preferably such that the component along the radial direction is larger than that in the circumferential direction.

Moreover, the sealed fluid may be a liquid, or may be a mist mixture of a liquid and a gas.

1 is a longitudinal sectional view showing an example of a mechanical seal in Example 1 of the present invention; FIG. It is the figure which looked at the sliding surface of the stationary seal ring from the axial direction. It is an AA sectional view. FIG. 4 is a partially enlarged view of the sliding surface of the stationary seal ring; 4(a) to 4(c) are schematic diagrams for explaining an operation in which the sealed liquid sucked from the inner diameter side of the liquid guiding groove portion flows out between the sliding surfaces at the initial stage of relative rotation. FIG. FIG. 4 is an enlarged view of a main portion of the sliding surface of the stationary seal ring; It is the figure which looked at the sliding surface of the stationary seal ring in Example 2 of this invention from the axial direction. FIG. 4 is an enlarged view of a main portion of the sliding surface of the stationary seal ring; FIG. 11 is a view of the sliding surface of the stationary seal ring in Example 3 of the present invention as seen from the axial direction; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 4 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 5 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 6 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 7 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 8 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 9 of the present invention; FIG. 10 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 10 of the present invention; FIG. 11 is an enlarged view of a main portion of a sliding surface of a stationary seal ring in Example 11 of the present invention;

A mode for carrying out the sliding component according to the present invention will be described below based on an embodiment.

A sliding component according to Example 1 will be described with reference to FIGS. 1 to 6. FIG. In addition, in the present embodiment, a form in which the sliding part is a mechanical seal will be described as an example. In addition, the inner diameter side of the sliding parts constituting the mechanical seal will be described as the sealed liquid side (high pressure side), and the outer diameter side will be described as the atmosphere side (low pressure side) as the leakage side. Also, for convenience of explanation, dots may be attached to grooves formed on the sliding surface in the drawings.

The mechanical seal for general industrial machinery shown in FIG. 1 is of an outside type for sealing against a liquid to be sealed F that is about to leak from the inner diameter side to the outer diameter side of the sliding surface. The stationary seal ring 10 is axially urged by the bellows 7, so that the sliding surface 11 of the stationary seal ring 10 and the sliding surface 21 of the rotary seal ring 20 closely slide against each other. The sliding surface 21 of the rotary seal ring 20 is a flat surface, and this flat surface is not provided with a recess.

The stationary seal ring 10 and the rotary seal ring 20 are typically formed of a combination of SiC (hard material) or SiC (hard material) and carbon (soft material). Examples of SiC include sintered bodies using boron, aluminum, carbon, etc. as sintering aids, materials consisting of two or more phases with different components and compositions, for example, SiC in which graphite particles are dispersed, reaction-sintered SiC composed of SiC and Si, SiC-TiC, SiC-TiN, and the like. Metal materials, resin materials, surface modification materials (coating materials), composite materials, etc. are also applicable in addition to the sliding materials described above.

As shown in FIG. 2, the rotary seal ring 20 slides relative to the stationary seal ring 10 as indicated by the arrows, and the sliding surface 11 of the stationary seal ring 10 is provided with a plurality of dynamic pressure generating mechanisms 14 formed integrally with the base material constituting the sliding surface 11 and arranged evenly in the circumferential direction of the stationary seal ring 10. A portion of the sliding surface 11 other than the dynamic pressure generating mechanism 14 is a land 12 forming a flat end surface.

Next, the outline of the dynamic pressure generating mechanism 14 will be described with reference to FIGS. 2 to 4. FIG. In the following description, when the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other, the left side of the paper surface of FIG. 4 is the downstream side of the sealed liquid F flowing through the Rayleigh step 9A, and the right side of the paper surface of FIG. 4 is the upstream side of the sealed liquid F flowing through the Rayleigh step 9A.

The dynamic pressure generating mechanism 14 includes a liquid guide groove portion 15 as a deep groove portion that communicates with the atmosphere and extends in the inner diameter direction, a Rayleigh step 9A as a shallow groove portion that extends in the circumferential direction downstream from the inner diameter end portion of the liquid guide groove portion 15 concentrically with the stationary seal ring 10, and a trap portion 13 that gradually narrows the width of the flow path of the liquid guide groove portion 15 from the outer diameter side to the inner diameter side. That is, the dynamic pressure generating mechanism 14 has an inverted L shape when viewed from a direction orthogonal to the sliding surface 11 due to the liquid guiding groove portion 15 and the Rayleigh step 9A. It should be noted that the liquid guiding groove portion 15 of the first embodiment extends radially so as to be perpendicular to the axis of the stationary seal ring 10 . Further, the liquid guide groove portion 15 and the Rayleigh step 9A communicate with each other, and a step 18 in the depth direction is formed in the communicating portion.

Further, the Rayleigh step 9A is formed with a wall portion 9a perpendicular to the rotation direction at the downstream end portion. In addition, the wall portion 9a is not limited to being perpendicular to the rotation direction, and may be inclined with respect to the rotation direction, or may be formed in a stepped shape.

The liquid guiding groove portion 15 has an opening portion 15a that opens to the outer periphery of the stationary seal ring 10 and communicates with the atmosphere side. Further, the depth dimension L10 of the liquid guiding groove portion 15 is deeper than the depth dimension L20 of the Rayleigh step 9A (L10>L20). Specifically, the depth L10 of the liquid guiding groove portion 15 in the first embodiment is set to 100 μm, and the depth L20 of the Rayleigh step 9A is set to 5 μm. That is, between the liquid guiding groove portion 15 and the Rayleigh step 9A, a step 18 in the depth direction is formed by the downstream side wall surface 15b of the liquid guiding groove portion 15 and the bottom surface of the Rayleigh step 9A. If the depth dimension of the liquid guiding groove portion 15 is formed deeper than the depth dimension of the Rayleigh step 9A, the depth dimensions of the liquid guiding groove portion 15 and the Rayleigh step 9A can be freely changed, and preferably the dimension L10 is five times or more the dimension L20.

Although the bottom surface of the Rayleigh step 9A is flat and parallel to the land 12, the flat surface may be provided with fine recesses or may be inclined with respect to the land 12. FIG. Furthermore, the two arc-shaped surfaces extending in the circumferential direction of the Rayleigh step 9A are perpendicular to the bottom surface of the Rayleigh step 9A. The bottom surface 15d of the liquid guide groove 15 is flat and parallel to the land 12. However, it is possible to provide a fine concave portion on the flat surface or form it so as to be inclined with respect to the land 12. Further, referring to FIG. 3, the liquid guide groove portion 15 has a downstream side wall surface 15b and an upstream side wall surface 15c that extend radially and face each other in the circumferential direction, and a bottom surface 15d perpendicular to the wall surfaces 15b and 15c. That is, the downstream side wall surface 15b, the upstream side wall surface 15c, and the bottom surface 15d form the inner surface of the liquid guiding groove portion 15. As shown in FIG.

The trap portion 13 is composed of a trap piece 13A extending radially inward from the downstream side wall surface 15b of the liquid guide groove portion 15 located on the outer diameter side of the Rayleigh step 9A toward the center of the liquid guide groove portion 15 in the circumferential direction, and a trap piece 13B extending radially inward from the upstream side wall surface 15c of the liquid guide groove portion 15 toward the center side of the liquid guide groove portion 15 in the circumferential direction facing the trap piece 13A. These trap pieces 13A and 13B are arranged line-symmetrically with respect to an imaginary center line extending in the radial direction of the liquid guide groove portion 15 as a reference. In the following description, the trap piece 13A will be described unless otherwise specified, and the description of the trap piece 13B will be omitted.

The trap piece 13A has a low-pressure side wall surface 13a extending radially inward from the downstream side wall surface 15b of the liquid guiding groove portion 15 positioned radially outward of the low-pressure side wall surface 9c extending in the circumferential direction of the Rayleigh step 9A toward the center of the liquid guiding groove portion 15, and a high-pressure side wall surface continuing from the low pressure side wall surface 9c of the Rayleigh step 9A and extending radially inward from the downstream side wall surface 15b of the liquid guiding groove portion 15 toward the center side in the circumferential direction of the liquid guiding groove portion 15. 13c and are formed. The low-pressure side wall 13a and the high-pressure side wall 13c of the trap piece 13A are flat surfaces.

The trap piece 13A has an end surface facing the sliding surface 21 of the rotary seal ring 20 that is flush with and continuous with the land 12 . Also, the trap piece 13A is continuous from the end surface facing the sliding surface 21 of the rotary seal ring 20, which is flush with the land 12, to the bottom surface 15d of the liquid guiding groove portion 15. As shown in FIG.

Next, the operation during relative rotation between the stationary seal ring 10 and the rotary seal ring 20 will be described. First, when the rotary seal ring 20 is not rotating and the general industrial machine is not in operation, the sealed liquid F on the outer diameter side of the sliding surfaces 11 and 21 slightly enters between the sliding surfaces 11 and 21 due to capillary action, and the dynamic pressure generating mechanism 14 is in a state where the sealed liquid F remaining when the general industrial machine is stopped and the air entering from the inner diameter side of the sliding surfaces 11 and 21 are mixed. Since the sealed liquid F has a higher viscosity than gas, the amount of liquid leaking from the dynamic pressure generating mechanism 14 to the low pressure side when the general industrial machine is stopped is small.

When there is almost no liquid F left in the dynamic pressure generating mechanism 14 when the general industrial machine is stopped, when the rotary seal ring 20 rotates relative to the stationary seal ring 10 (see the black arrow in FIG. 2), as shown in FIG. A dynamic pressure is generated in A.

The pressure is highest in the vicinity of the wall portion 9a, which is the downstream end of the Rayleigh step 9A, and the low-pressure side fluid A flows out from the vicinity of the wall portion 9a to the surroundings as indicated by an arrow L3. Incidentally, the pressure gradually decreases toward the upstream side of the Rayleigh step 9A.

When the stationary seal ring 10 and the rotary seal ring 20 rotate relative to each other, the high-pressure sealed liquid F flows between the sliding surfaces 11 and 21 from the inner diameter side at any time, so that so-called fluid lubrication is achieved. At this time, since the sealed liquid F in the vicinity of the Rayleigh step 9A is at a high pressure particularly on the downstream side of the Rayleigh step 9A as described above, it remains positioned on the land 12 as indicated by the arrow H1 and hardly enters the Rayleigh step 9A. On the other hand, since the liquid guide groove 15 is a deep groove and communicates with the low pressure side, the sealed liquid F in the vicinity of the liquid guide groove 15 easily enters the liquid guide groove 15 as indicated by an arrow H2. In addition, since the sealed liquid F is a liquid and has a large surface tension, it easily moves along the side wall surfaces of the liquid guide groove 15 and enters the liquid guide groove 15 .

Next, the operation of flowing out the sealed liquid F sucked into the liquid guiding groove portion 15 between the sliding surfaces 11 and 21 will be described.

When almost no liquid to be sealed F remains in the dynamic pressure generating mechanism 14, when the rotary seal ring 20 rotates relative to the stationary seal ring 10 (see the black arrow in FIG. 2), as shown in FIG. After that, as shown in FIG. 5(b), when the droplet reaches a certain volume, it passes through the trap section 13 due to the relatively low pressure formed upstream of the Rayleigh step 9A, and is drawn into the Rayleigh step 9A as indicated by H4. At the same time, the sealed liquid F newly enters the liquid guiding groove portion 15 and becomes a droplet H3'. At this time, a larger amount of the sealed liquid F enters the liquid guiding groove portion 15 than in the initial state of the relative rotation in FIG. 5(a).

After that, as shown in FIG. 5(c), the sealed liquid F drawn into the Rayleigh step 9A receives a large shearing force from the rotary seal ring 20, moves downstream inside the Rayleigh step 9A while increasing the pressure, and flows out from the vicinity of the wall portion 9a to the peripheral portion thereof as indicated by an arrow H5. At the same time, a larger amount of the sealed liquid F newly enters the liquid guiding groove portion 15 to form a liquid droplet H3'', and the liquid droplet H3' is drawn into the Rayleigh step 9A as indicated by symbol H4'.

After that, the amount of the sealed liquid F entering the liquid guide groove 15 increases compared to the state shown in FIG. In a steady state, the high-pressure sealed liquid F flows between the sliding surfaces 11 and 21 from the outer diameter side thereof or from the Rayleigh step 9A at any time, and fluid lubrication is achieved as described above. It should be noted that it takes a transitional short time to reach a steady state through FIGS. Further, when the sealed liquid F remains in the dynamic pressure generating mechanism 14 when the general industrial machine is stopped, the operation starts from any one of the state shown in FIG. 5A, the state shown in FIG. 5B, the state shown in FIG.

Here, since the liquid guide groove portion 15 is a deep groove portion and communicates with the low pressure side, the sealed liquid F indicated by the arrow H5 is easily drawn into the adjacent liquid guide groove portion 15, the amount of the sealed liquid F between the sliding surfaces 11 and 21 is stabilized, and high lubricity can be maintained. In addition, since the interfacial tension of a liquid against a solid is greater than that of a gas, the liquid to be sealed F is likely to be retained between the sliding surfaces 11 and 21, and the atmosphere is more likely to be discharged to the outer diameter side than the stationary seal ring 10 and the rotary seal ring 20.

Referring to FIG. 5, as exemplified by droplets H3, H3', and H3'', the trap section 13 has low-pressure side walls 13a and 13a of the trap pieces 13A and 13B, which are slanted from the wall surfaces 15b and 15c toward the center of the liquid guide groove 15 toward the inner diameter side, which is the inflow direction of the liquid F to be sealed. Even if the flow path of is narrowed, the movement of the sealed liquid F is less likely to be hindered.

Further, referring to FIG. 6, since the high pressure side wall surface 13c of the trap piece 13A is continuous with the low pressure side wall surface 9c of the Rayleigh step 9A as indicated by arrow H6, the sealed liquid F can be guided directly from the high pressure side wall surface 13c to the low pressure side wall surface 9c of the Rayleigh step 9A. Therefore, the efficiency of drawing the sealed liquid F into the Rayleigh step 9A is good.

Further, as shown in FIG. 6, since the mechanical seal of this embodiment is of the outside type, the centrifugal force generated by the rotation of the rotary seal ring 20 acts on the liquid F to be sealed, as indicated by arrow C, so that the liquid F to be sealed in the liquid guiding groove portion 15 is urged in the direction of leakage toward the atmosphere side, which is the outer diameter side. However, since the liquid to be sealed F is a liquid and has a higher viscosity than gas, the trap section 13 can resist the centrifugal force acting on the liquid to be sealed F by the high-pressure side walls 13c, 13c of the trap pieces 13A, 13B, which are inclined toward the outer diameter side, which is the direction in which the liquid to be sealed F leaks, toward the wall surfaces 15b, 15c from the center in the circumferential direction of the liquid guide groove 15. Therefore, leakage to the atmosphere can be suppressed. Furthermore, since the high-pressure side wall surface 13c of the trap piece 13A can guide the sealed liquid F directly to the Rayleigh step 9A as described above, the efficiency of drawing the sealed liquid F from the liquid guide groove 15 into the Rayleigh step 9A can be enhanced using centrifugal force.

In the trap section 13, since the width between the trap pieces 13A and 13B is narrowed, the centrifugal force acting on the liquid F between the trap pieces 13A and 13B is resisted by the surface tension acting on the liquid F between the trap pieces 13A and 13B. As a result, as indicated by the halftone dots in FIG. 6, the ability to retain the sealed liquid F on the inner diameter side of the trap portion 13 is enhanced.

As described above, during relative rotation between the stationary seal ring 10 and the rotary seal ring 20, the Rayleigh step 9A draws the low-pressure side fluid A on the atmosphere side through the liquid guide groove 15 to generate dynamic pressure. Since the liquid guiding groove portion 15 has a large groove depth and a large volume, a large amount of the sealed liquid F supplied to the atmosphere side of the sliding surface 11 can be recovered and returned to the Rayleigh step 9A, and the large area extending to the low pressure side of the sliding surface 11 can be utilized to improve lubricity. Further, since the trap portion 13 is provided in the liquid guiding groove portion 15, the sealed liquid F is held in the liquid guiding groove portion 15 against the centrifugal force generated in the sealed liquid F due to the relative rotation of the stationary seal ring 10, thereby suppressing the leakage of the sealed liquid F to the atmosphere side located on the outer diameter side.

Further, since a large amount of the sealed liquid F is held in the liquid guiding groove portion 15, a sufficient amount of the sealed liquid F drawn into the Rayleigh step 9A can be ensured, and even if the amount of the sealed liquid F held in the liquid guiding groove portion 15 increases or decreases in a short period of time, the amount of the sealed liquid F drawn into the Rayleigh step 9A can be kept substantially constant, and poor lubrication of the sliding surfaces 11 and 21 can be avoided. Further, since the liquid guide groove portion 15 communicates with the low pressure side, the pressure in the liquid guide groove portion 15 is lower than the pressure of the sealed liquid F between the sliding surfaces 11 and 21, and the sealed liquid F in the vicinity of the liquid guide groove portion 15 is easily drawn into the liquid guide groove portion 15.

Further, the liquid guiding groove portion 15 extends in the radial direction. Specifically, the liquid guiding groove portion 15 extends in a direction orthogonal to the central axis of the stationary seal ring 10, and is arranged in the circumferential direction so as to intersect the Rayleigh step 9A from the outer diameter side end of the groove portion 15, so that it is less susceptible to the inertia of the flow of the sealed liquid F generated in the Rayleigh step 9A and the dynamic pressure. As a result, the sealed liquid F and the low-pressure side fluid A adhering to the inner surface of the stationary seal ring 10 are less likely to be directly sucked into the Rayleigh step 9A from the inner diameter side of the liquid guiding groove portion 15. As shown in FIG. Further, the sealed liquid F can be held in the liquid guide groove portion 15 without being directly affected by the dynamic pressure.

The trap pieces 13A and 13B are axially continuous from the end surface facing the sliding surface 21 of the rotary seal ring 20 to the bottom surface 15d of the liquid guiding groove portion 15, thereby increasing the rigidity against external forces acting in the axial direction. In addition, since the trap pieces 13A and 13B are continuous with the downstream side wall surface 15b and the upstream side wall surface 15c of the liquid guiding groove portion 15, respectively, the rigidity in the circumferential direction is also enhanced. That is, by extending the trap pieces 13A and 13B from the downstream side wall surface 15b, the upstream side wall surface 15c, and the bottom surface 15d of the liquid guiding groove portion 15, the trap portion 13 with high rigidity can be easily configured.

Further, since the trap portion 13 is arranged at the intersection of the liquid guide groove portion 15 and the Rayleigh step 9A, it can hold the sealed liquid F moving from the liquid guide groove portion 15 to the Rayleigh step 9A and reliably generate dynamic pressure.

Further, since the trap portion 13 is formed integrally with the base material forming the sliding surface 11, the trap portion 13 can be easily formed.

In addition, since the width of the liquid guide groove portion 15 in the circumferential direction can be shortened and more can be arranged in the circumferential direction of the stationary seal ring 10, the degree of freedom in design is high. The liquid guiding groove portion 15 is not limited to the direction perpendicular to the central axis of the stationary seal ring 10, and may be inclined from the position perpendicular to the central axis of the stationary seal ring 10, but the inclination is preferably less than 45 degrees. Furthermore, the shape of the liquid guiding groove portion 15 can be freely changed such as an arc shape.

Further, in the communicating portion between the Rayleigh step 9A and the liquid guiding groove portion 15, a step 18 is formed by the downstream side surface of the liquid guiding groove portion 15 and the bottom surface of the Rayleigh step 9A, so that the sealed liquid F can be held in the liquid guiding groove portion 15 without being directly affected by the dynamic pressure.

Further, since the Rayleigh step 9A communicates with the liquid guiding groove portion 15 over the entire width in the radial direction, the opening area of the Rayleigh step 9A to the liquid guiding groove portion 15 can be secured, and the sealed liquid F held in the liquid guiding groove portion 15 can be efficiently sucked up.

Further, since the static seal ring 10 is provided with the dynamic pressure generating mechanism 14, the inside of the liquid guide groove portion 15 can be easily kept close to the atmospheric pressure when the static seal ring 10 and the rotary seal ring 20 rotate relative to each other.

In the first embodiment, the liquid guiding groove portion 15 and the Rayleigh step 9A form an inverted L shape when viewed from the direction perpendicular to the sliding surface 11. However, for example, the liquid guiding groove portion 15 and the Rayleigh step 9A may communicate smoothly without intersecting each other, such as in a straight line or an arc shape.

Further, the step 18 may not be provided in the communicating portion between the liquid guiding groove portion 15 and the Rayleigh step 9A. For example, the liquid guiding groove portion 15 and the Rayleigh step 9A may communicate with each other through an inclined surface. In this case, for example, the portion having a depth dimension of 5 μm or less can be the Rayleigh step 9A as the shallow groove portion, and the portion deeper than 5 μm can be the liquid guiding groove portion 15 as the deep groove portion.

Further, the shallow groove portion is not limited to extending in the circumferential direction concentrically with the stationary seal ring. Further, the shallow groove portion may extend linearly from the deep groove portion, or may extend in a meandering manner.

Further, the trap portion 13 may be composed only of the trap piece 13A arranged on the side of the Rayleigh step 9A, which is the dynamic pressure generating groove, the dimensions of the trap piece 13A may be changed as appropriate, and the trap portion 13 may be arranged radially away from the low-pressure side wall surface 9c of the Rayleigh step 9A. Similarly, the trap portion 13 may be composed only of the trap piece 13B arranged on the side facing the Rayleigh step 9A.

Moreover, although the trap piece 13A has exemplified the form in which it is flush with the land 12, it may be recessed from the land 12 in the axial direction, for example. In addition, the trap piece 13A is exemplified as continuing in the axial direction to the bottom surface 15d of the liquid guiding groove portion 15, but for example, the lower end portion of the trap piece 13A may be separated from the bottom surface 15d of the liquid guiding groove portion 15, or a part of the trap piece 13A in the axial direction may be divided in the middle. That is, the trap piece 13A only needs to be capable of suppressing the leakage of the sealed liquid F from the liquid guide groove 15 to the atmosphere due to the centrifugal force, and the shape thereof may be changed as appropriate.

Further, the trap piece 13A has been described as being formed integrally with the base material forming the sliding surface 11, but this is not limiting, and a trap piece formed separately from the base material forming the sliding surface 11 may be fixed to the inner surface of the liquid guide groove 15.

Next, a sliding component according to Example 2 will be described with reference to FIGS. 7 and 8. FIG. It should be noted that the description of the configuration that is the same as that of the first embodiment and overlaps will be omitted.

As shown in FIGS. 7 and 8, the dynamic pressure generating mechanism 141 provided in the stationary seal ring 101 includes the liquid guide groove portion 15, a Rayleigh step 9A, a reverse Rayleigh step 9B as a shallow groove portion extending circumferentially from the inner diameter side end of the liquid guide groove portion 15 toward the upstream side concentrically with the stationary seal ring 101, and the trap portion 13. That is, the dynamic pressure generating mechanism 141 has a T shape when viewed from a direction perpendicular to the sliding surface 11 . The reverse Rayleigh step 9B is formed with the same depth dimension of 5 μm as the Rayleigh step 9A.

The trap piece 13B has a low pressure side wall surface 13a extending radially inward from the upstream side wall surface 15c of the liquid guiding groove portion 15 positioned radially outward of the low pressure side wall surface 9c extending in the circumferential direction of the reverse Rayleigh step 9B toward the center of the liquid guiding groove portion 15. A side wall surface 13c is formed.

When the rotary seal ring 20 rotates counterclockwise on the page indicated by the solid arrow in FIG. 7, the low-pressure side fluid A moves in the order of arrows L1, L2, and L3 to generate dynamic pressure in the Rayleigh step 9A. When the rotary seal ring 20 rotates clockwise as indicated by the dotted arrow in FIG. 7, the low-pressure side fluid A moves in the order of arrows L1, L2', and L3' to generate dynamic pressure in the reverse Rayleigh step 9B. That is, when the rotary seal ring 20 rotates clockwise in FIG. 7, the reverse Rayleigh step 9B functions as a Rayleigh step, and the Rayleigh step 9A functions as a reverse Rayleigh step.

In this way, the Rayleigh step 9A and the reverse Rayleigh step 9B extend from the liquid guide groove portion 15 on both sides in the circumferential direction, and either one of the Rayleigh step 9A or the reverse Rayleigh step 9B can be used as a shallow groove portion for generating dynamic pressure, so that the stationary seal ring 101 and the rotary seal ring 20 can be used regardless of the relative rotation direction.

Also, the Rayleigh step 9A in the dynamic pressure generating mechanism 141 is circumferentially adjacent to the opposite Rayleigh step 9B of the adjacent dynamic pressure generating mechanism 141'. According to this, since the sealed liquid F flowing out from the vicinity of the wall portion 9a of the Rayleigh step 9A in the dynamic pressure generating mechanism 141 to the peripheral part thereof and about to move to the inner diameter side is sucked from the reverse Rayleigh step 9B in the adjacent dynamic pressure generating mechanism 141', leakage of the sealed liquid F to the low pressure side can be reduced.

In addition, when the rotary seal ring 20 rotates counterclockwise on the paper surface indicated by the solid arrow in FIG. 8, the trap section 13 can suppress leakage of the sealed liquid F to the atmosphere side located on the outer diameter side, as in the first embodiment. When the rotating seal ring 20 rotates clockwise as indicated by the dotted arrow in FIG. 8, the trap section 13 does not hinder the movement of the sealed liquid F from the atmosphere side to the sealed liquid F side. Surface tension is generated in the liquid to be sealed F existing between the trap pieces 13A and 13B, and the surface tension counteracts the centrifugal force acting on the liquid to be sealed F. As shown by the halftone dots, the holding capacity of the liquid to be sealed F on the inner diameter side of the trap section 13 is enhanced. That is, the function of retaining the liquid to be sealed F can be exhibited corresponding to the stationary seal ring 101 that rotates in both circumferential directions.

Although the Rayleigh step 9A and the reverse Rayleigh step 9B have the same depth dimension in the second embodiment, they may have different depth dimensions. In addition, both may have the same or different circumferential length and radial width.

Alternatively, the Rayleigh step 9A of the dynamic pressure generating mechanism 141 and the reverse Rayleigh step 9B of the adjacent dynamic pressure generating mechanism 141' may be separated by a long distance in the circumferential direction to further increase the pressure separating the sliding surfaces 11 and 21.

Next, a sliding component according to Example 3 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted.

As shown in FIG. 9 , the static seal ring 102 is provided with a plurality of dynamic pressure generating mechanisms 141 and a plurality of specific dynamic pressure generating mechanisms 16 . The specific dynamic pressure generating mechanism 16 includes a liquid guide groove portion 161 that communicates with the high pressure side, a Rayleigh step 17A that extends in the circumferential direction from the outer diameter side end of the liquid guide groove portion 161 toward the downstream side concentrically with the stationary seal ring 102, and a reverse Rayleigh step 17B that extends in the circumferential direction concentrically with the stationary seal ring 102 from the outer diameter side end portion of the liquid guide groove portion 161 toward the upstream side. The liquid guide groove portion 161 and the liquid guide groove portion 15 are formed at corresponding positions in the circumferential direction. The liquid guiding groove portion 161 functions as a deep groove portion of the specific dynamic pressure generating mechanism 16 , and the Rayleigh step 17 A and the reverse Rayleigh step 17 B function as shallow groove portions of the specific dynamic pressure generating mechanism 16 .

The Rayleigh step 9A and the reverse Rayleigh step 9B of the dynamic pressure generating mechanism 141 are formed longer in the circumferential direction than the Rayleigh step 17A and the reverse Rayleigh step 17B of the specific dynamic pressure generating mechanism 16 . The depth dimension of the Rayleigh step 17A and the reverse Rayleigh step 17B is 5 μm, which is the same as that of the Rayleigh step 9A and the reverse Rayleigh step 9B. Further, the radial width of the Rayleigh step 17A and the reverse Rayleigh step 17B is smaller than the radial width of the Rayleigh step 9A and the reverse Rayleigh step 9B. That is, the volume of the dynamic pressure generating mechanism 141 is larger than the volume of the specific dynamic pressure generating mechanism 16 .

When the rotary seal ring 20 rotates counterclockwise on the page indicated by the solid arrow in FIG. 9, the sealed liquid F moves in the order of arrows L11, L12, and L13 to generate dynamic pressure in the Rayleigh step 17A. When the rotary seal ring 20 rotates clockwise as indicated by the dotted arrow in FIG. 9, the liquid to be sealed F moves in the order of arrows L11, L12', and L13' to generate dynamic pressure in the reverse Rayleigh step 17B. In this way, dynamic pressure can be generated in the specific dynamic pressure generating mechanism 16 regardless of the relative rotational direction between the stationary seal ring 102 and the rotary seal ring 20 .

Further, the dynamic pressure generated by the specific dynamic pressure generating mechanism 16 separates the sliding surfaces 11 and 21 to form an appropriate liquid film, and the dynamic pressure generating mechanism 141 recovers the sealed liquid F that is about to leak from the sliding surface 11 to the low pressure side.

Further, since the volume of the dynamic pressure generating mechanism 141 is larger than the volume of the specific dynamic pressure generating mechanism 16, the suction force of the Rayleigh step 9A and the reverse Rayleigh step 9B of the dynamic pressure generating mechanism 141 can be increased to adjust the dynamic pressure balance between the dynamic pressure generating mechanism 141 on the low pressure side and the specific dynamic pressure generating mechanism 16 on the high pressure side.

Further, since the wall portion 9a, which is the terminal end of the dynamic pressure generating mechanism 141, and the wall portion 17a, which is the terminal end of the specific dynamic pressure generating mechanism 16, are displaced in the circumferential direction, the pressure can be distributed in the circumferential direction of the sliding surfaces 11 and 21 and the balance is good.

The circumferential length of the Rayleigh step 9A and the reverse Rayleigh step 9B may be the same as the Rayleigh step 17A and the reverse Rayleigh step 17B, or may be shorter than the Rayleigh step 17A and the reverse Rayleigh step 17B. Moreover, the Rayleigh step 17A and the reverse Rayleigh step 17B may be formed with a depth dimension different from that of the Rayleigh step 9A and the reverse Rayleigh step 9B. Also, the radial width of the Rayleigh step 17A and the reverse Rayleigh step 17B may be formed to be greater than the radial width of the Rayleigh step 9A and the reverse Rayleigh step 9B. Preferably, the volume of the dynamic pressure generating mechanism 141 should be larger than the volume of the specific dynamic pressure generating mechanism 16 .

The sliding surface 11 has a radial dimension from the outer edge of the sliding surface 11 to the outer edge of the Rayleigh step 9A of the dynamic pressure generating mechanism 141, a radial dimension from the inner edge of the Rayleigh step 9A of the dynamic pressure generating mechanism 141 to the outer edge of the Rayleigh step 17A of the specific dynamic pressure generating mechanism 16, and an inner diameter edge of the sliding surface 11 from the inner diameter edge of the Rayleigh step 17A of the specific dynamic pressure generating mechanism 16. may be changed as appropriate, whereby the amount of the sealed liquid F leaking from between the sliding surfaces 11 and 21 to the atmosphere side and the amount of the sealed liquid F recovered by the dynamic pressure generating mechanism can be more suitably balanced according to the rotational speed of the rotary seal ring 20 and the pressure of the sealed liquid F. That is, leakage of the sealed liquid F to the atmosphere side can be suppressed.

Next, a stationary seal ring according to Example 4 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 142 will be described here.

The dynamic pressure generating mechanism 142 includes a liquid guiding groove portion 151, a Rayleigh step 91A extending circumferentially downstream (left side in the drawing) from the radial center of the liquid guiding groove portion 151, a reverse Rayleigh step 91B extending circumferentially upstream (right side in the drawing) from the radially inner diameter side end of the liquid guiding groove portion 151, which is radially inner than the Rayleigh step 91A, and a trap portion 131. The trap portion 131 is composed of trap pieces 131A and 131B arranged alternately in the radial direction.

As a result, when the rotary seal ring 20 rotates counterclockwise, in the trap portion 131, a centrifugal force acts on the sealed liquid F in the liquid guide groove portion 151 toward the atmosphere side. are In other words, since the trap portion 131 makes it difficult for the sealed liquid F to move radially in a straight line, the function of retaining the sealed liquid F in the liquid guiding groove portion 151 can be enhanced.

Further, in the trap portion 131, since the width between the trap pieces 131A and 131B is narrowed, surface tension is generated in the liquid to be sealed F existing between the trap pieces 131A and 131B, and the surface tension counteracts the centrifugal force acting on the liquid to be sealed F. As shown by the halftone dot portion, the ability to hold the liquid to be sealed F on the inner diameter side of the trap portion 131 is enhanced.

Next, a stationary seal ring according to Example 5 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 143 will be described here.

The dynamic pressure generating mechanism 143 includes a Rayleigh step 9A, a reverse Rayleigh step 9B, a liquid guiding groove portion 152, and a trap portion 132. The trap portion 132 includes a plurality of trap pieces 132A arranged at predetermined intervals from the vicinity of the opening 152a of the liquid guide groove portion 152 to the vicinity of the inner diameter side end portion intersecting with the Rayleigh step 9A, a plurality of trap pieces 132B arranged line-symmetrically with respect to the trap piece 132A with reference to an imaginary center line extending in the radial direction of the liquid guide groove portion 152, and four trap pieces 13 adjacent to each other at the circumferential center portion of the liquid guide groove portion 152. 2A, 132A, 132B, and a plurality of trap pieces 132C arranged in a portion surrounded by 132B.

The trap piece 132A extends radially outward from the downstream side of the liquid guide groove 152 toward the center of the liquid guide groove 152 in the circumferential direction. Further, the trap piece 132A is formed with a low-pressure side wall surface 132a extending radially outward from the downstream side of the liquid guide groove 152 toward the upstream side, a central side wall surface 132b perpendicular to the upstream end of the low-pressure side wall surface 132a and extending radially inward from the upstream end, and a downstream side wall surface 132c perpendicular to the radially inner end of the central side wall 132b and extending radially inward from the downstream end.

The trap piece 132C is formed axisymmetrically with respect to an imaginary center line extending in the radial direction of the liquid guide groove 152, and extends from the circumferential central portion of the liquid guide groove 152 to the downstream inner diameter side and the upstream inner diameter side. The trap piece 132C includes low-pressure side wall surfaces 132d and 132d extending from the circumferential center of the liquid guide groove 152 to the downstream and upstream inner diameter sides, central side wall surfaces 132e and 132e extending radially inwardly from the ends of the low-pressure side walls 132d and 132d toward the upstream side or downstream side perpendicular to the upstream side, and radially inner side surfaces of the central side wall surfaces 132e and 132e. Inner side wall portions 132f, 132f are formed that are perpendicular to the end portion and extend radially outward from the end portion toward the upstream side or the downstream side. The trap piece 132</b>C has an end surface facing the sliding surface 21 of the rotary seal ring 20 flush with the land 12 and continues to the bottom surface 152 d of the liquid guide groove 152 in the axial direction.

The downstream ends of the trap pieces 132C overlap and alternate with the upstream ends of the adjacent trap pieces 132A in the circumferential direction, and the upstream ends of the trap pieces 132C overlap and alternate with the downstream ends of the adjacent trap pieces 132B in the circumferential direction.

As a result, in the trap portion 132, the central side wall surfaces 132b, 132b of the trap pieces 132A, 132B that are inclined radially inward toward the inflow direction of the sealed liquid F, the low-pressure side wall surfaces 132d, 132d, and the central side wall surfaces 132e, 132e of the trap piece 132C function as guide surfaces that guide the liquid F toward the Rayleigh step 9A. It is difficult to prevent entry into the liquid guiding groove portion 152 .

In addition, in the trap section 132, since the width between the trap pieces 132A, 132B, and 132C is narrowed, surface tension is generated in the liquid to be sealed F existing between the trap pieces 132A, 132B, and 132C, and the surface tension counteracts the centrifugal force acting on the liquid to be sealed F. As shown by the halftone dots, the ability to hold the liquid to be sealed F on the inner diameter side of the trap section 132 is enhanced.

In addition, since the trap piece 132C can collect the sealed liquid F that is about to leak from the liquid guide groove 152 to the atmosphere side by the inner diameter side walls 132f, 132f, it is possible to suitably suppress the leakage of the sealed liquid F to the atmosphere side.

Moreover, the trap piece 132C is continuous in the axial direction to the bottom surface 152d of the liquid guiding groove portion 152, and the rigidity against the external force acting in the axial direction is enhanced. That is, by extending the trap piece 132C from the bottom surface 152d of the liquid guide groove 152, the trap portion 132 with high rigidity can be easily configured.

Next, a stationary seal ring according to Example 6 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 144 will be described here.

The dynamic pressure generating mechanism 144 includes a Rayleigh step 9A, a reverse Rayleigh step 9B, a liquid guiding groove portion 153, and a trap portion 133. The trap portion 133 includes a plurality of trap pieces 133A arranged at predetermined intervals from the vicinity of the opening 153a of the liquid guide groove portion 153 to the vicinity of the inner diameter side end portion intersecting the Rayleigh step 9A, a plurality of trap pieces 133B arranged line-symmetrically with respect to the trap pieces 133A with respect to the imaginary radial center line of the liquid guide groove portion 153, and four trap pieces 133 adjacent to each other at the circumferential center of the liquid guide groove portion 153. A, 133A, 133B, and a plurality of trap pieces 133C arranged at locations surrounded by 133B.

The trap piece 133</b>A extends perpendicularly to the downstream side wall surface 153 b of the liquid guide groove 153 toward the radially central portion of the liquid guide groove 153 . The trap piece 133C extends parallel to the trap pieces 133A and 133B.

As a result, since the width between the trap pieces 133A, 133B, and 133C is narrowed in the trap portion 133, surface tension is generated in the sealed liquid F existing between the trap pieces 133A, 133B, and 133C, and the surface tension counteracts the centrifugal force acting on the sealed liquid F. As shown by the halftone dot portion, the ability to hold the sealed liquid F on the inner diameter side of the trap portion 133 is enhanced.

Next, a stationary seal ring according to Example 7 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 145 will be described here.

The dynamic pressure generating mechanism 145 includes a Rayleigh step 9A, a reverse Rayleigh step 9B, a liquid guiding groove portion 154, and a trap portion . The trap portion 134 is arranged at the opening 154a of the liquid guiding groove portion 154, and is composed of a trap piece 134A extending from a downstream side wall surface 154b of the liquid guiding groove portion 154 toward the center of the liquid guiding groove portion 154 in the circumferential direction, and a trap piece 134B arranged line-symmetrically with respect to the trap piece 134A with respect to an imaginary center line extending in the radial direction of the liquid guiding groove portion 154.

As a result, since the width between the trap pieces 134A and 134B is narrowed in the trap portion 134, surface tension is generated in the liquid to be sealed F existing between the trap pieces 134A and 134B, and the surface tension counteracts the centrifugal force acting on the liquid to be sealed F. As shown by the halftone dots, the ability to hold the liquid to be sealed F on the inner diameter side of the trap portion 133 is enhanced.

Moreover, since the trap portion 134 is arranged in the opening portion 154 a of the liquid guide groove portion 154 , the volume of the liquid guide groove portion 154 on the inner diameter side of the trap portion 134 can be preferably secured. That is, the amount of the sealed liquid F held in the liquid guiding groove portion 154 can be ensured. The trap portion is arranged at a position near the opening, which communicates with the low pressure side rather than the high pressure side of the liquid guide groove including the opening, so that the amount of the sealed liquid F held in the liquid guide groove can be ensured. .

Next, a stationary seal ring according to Example 8 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 146 will be described here.

The dynamic pressure generating mechanism 146 includes a Rayleigh step 92A, a reverse Rayleigh step 92B, a liquid guiding groove portion 155 radially extending from a radially central portion between the Rayleigh steps 92A and the reverse Rayleigh step 92B, and a trap portion 135. The trap portion 135 is formed at the inner diameter side end portion of the liquid guide groove portion 155 at a location where it intersects with the Rayleigh step 92A and the reverse Rayleigh step 92B.

As a result, if the rotating ring 20 rotates in a paper violent clock indicated by the solid line arrow, the trap portion 135, as shown in the arrow H10, most of the sealed liquid F flowing in from the inner diameter of the trap portion 135 and the inverted reply step 92b, as shown in the arrow H11. Since it is sucked into 92a, the inflow amount of the sealed liquid F flowing into the liquid -induced groove 155, as shown in the arrow H12, is reduced. As a result, leakage from the liquid guide groove 155 to the atmosphere can be relatively suppressed. Although direct illustration is omitted, the same applies when the rotary seal ring 20 rotates clockwise on the page, except that the direction of the arrow H11 is reversed.

Next, a stationary seal ring according to Example 9 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 147 will be described here.

The dynamic pressure generating mechanism 147 includes a Rayleigh step 93A, a reverse Rayleigh step 93B, a liquid guiding groove portion 156, and trap portions 136A and 136B. The trap portions 136A and 136B are deep grooves whose depth dimension is the same as the depth dimension of the liquid guide groove portion 156, and are arranged symmetrically with respect to the imaginary center line extending in the radial direction of the liquid guide groove portion 156 as a reference. The trap portion 136A is composed of a peripheral portion 136a extending in the circumferential direction from the inner diameter side end portion of the liquid guide groove portion 156 with the same curvature as that of the Rayleigh step 93A, and a radial portion 136b communicating with the peripheral portion 136a and extending in the radial direction. The peripheral portion 136a of the trap portion 136A communicates with the Rayleigh step 93A and the liquid guiding groove portion 156, and the peripheral portion 136a of the trap portion 136B communicates with the liquid guiding groove portion 156 and the reverse Rayleigh step 93B.

As a result, when the rotary seal ring 20 rotates counterclockwise in the paper surface indicated by the solid-line arrow, in the trap portions 136A and 136B, as indicated by the solid-line arrow H22, the liquid to be sealed F leaked from the reverse Rayleigh step 93B to the outer diameter side due to the centrifugal force flows into the diameter portion 136b of the trap portion 136B, and as indicated by the solid-line arrow H23, flows from the downstream side wall surface 156b of the liquid guiding groove portion 156 to the circumferential downstream side (the paper surface). Since the sealed liquid F leaked to the left side flows into the diameter portion 136b of the trap portion 136A, leakage from the dynamic pressure generating mechanism 147 to the atmosphere side can be suppressed.

Further, when the rotary seal ring 20 rotates clockwise as indicated by the dotted line arrow, in the trap portions 136A and 136B, as indicated by the dotted line arrow H20, the liquid to be sealed F leaked from the reverse Rayleigh step 93B toward the outer diameter side due to the centrifugal force flows into the diameter portion 136b of the trap portion 136A, and as indicated by the dotted line arrow H21, flows downstream in the circumferential direction from the downstream side wall surface 156b of the liquid guide groove portion 156 (to the right side of the paper surface). Since the sealed liquid F that has leaked out into the trap portion 136B flows into the diameter portion 136b of the trap portion 136B, leakage from the dynamic pressure generating mechanism 147 to the atmosphere side can be suppressed.

Further, the dynamic pressure generating mechanism 147 can hold the sealed liquid F not only in the liquid guide groove 156 but also in the traps 136A and 136B, and the sealed liquid F can flow into the Rayleigh step 93A and the reverse Rayleigh step 93B through the peripheral portions 136a and 136a, so that a larger amount of the sealed liquid F can be held.

Next, a stationary seal ring according to a tenth embodiment will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 148 will be described here.

The dynamic pressure generating mechanism 148 includes a Rayleigh step 9A, a reverse Rayleigh step 9B, a liquid guiding groove portion 157, and a trap portion 137. The trap portion 137 is composed of trap wall portions 137A and 137B having a plurality of protrusions protruding upstream or downstream from the downstream side wall surface 157b and the upstream side wall surface 157c of the liquid guiding groove portion 157. Incidentally, broken lines in the drawing indicate virtual wall surfaces.

The trap wall portions 137A and 137B are alternately arranged with a predetermined distance from each other, and between the trap wall portions 137A and 137B, a meandering groove 30 is formed that continuously meanders while bending on the downstream side wall surface 157b side and the upstream side wall surface 157c side. The trap walls 137A and 137B are arranged at a position where the end face facing the sliding surface 21 of the rotary seal ring 20 is 10 μm deeper than the Rayleigh step 9A and the reverse Rayleigh step 9B. The depth dimension of the end faces of the trap walls 137A and 137B facing the sliding surface 21 of the rotary seal ring 20 may be, for example, the same dimension as the Rayleigh step 9A and the reverse Rayleigh step 9B, a dimension shallower than the Rayleigh step 9A and the reverse Rayleigh step 9B, or a dimension deeper than the Rayleigh step 9A and the reverse Rayleigh step 9B, which is not limited to 10 μm.

As a result, the trap portion 137 makes it difficult for the sealed liquid F to move linearly from the sealed liquid F side toward the atmosphere side by means of the meandering groove 30, so that the function of holding the sealed liquid F in the liquid guiding groove portion 157 can be enhanced.

Further, in the trap portion 137, since the width of the serpentine groove 30 is narrowed by the trap wall portions 137A and 137B, surface tension is generated in the sealed liquid F existing in the serpentine groove 30, and the surface tension counteracts the centrifugal force acting on the sealed liquid F. As indicated by the halftone dot portion, the holding capacity of the sealed liquid F on the inner diameter side of the trap portion 137 is enhanced.

Next, a stationary seal ring according to Example 11 will be described with reference to FIG. It should be noted that descriptions of configurations that are the same as those of the second embodiment will be omitted. Also, only the form of the dynamic pressure generating mechanism 149 will be described here.

The dynamic pressure generating mechanism 149 includes a Rayleigh step 94A, a reverse Rayleigh step 94B, a liquid guiding groove portion 158, and a trap portion 138. The trap portion 138 is composed of trap wall portions 138A and 138B in which right-angled triangular convex portions 19 are continuously arranged in the radial direction and are inclined from the outer diameter side to the inner diameter side toward the radially central portion side of the liquid guiding groove portion 158 of the downstream side wall surface 158b or the upstream side wall surface 158c. An end surface that inclines from the outer diameter side to the inner diameter side of the convex portion 19 toward the radially central portion of the liquid guide groove portion 158 is referred to as an outer diameter side end surface 19a, and an end surface that extends from the end portion of the outer diameter side end surface 19a toward the liquid guide groove portion 158 in the radial direction center portion of the liquid guide groove portion 158 is referred to as an inner diameter side end surface 19b.

The trap walls 138A and 138B are arranged line-symmetrically with respect to the radial center line of the liquid guide groove 158 with a predetermined distance from each other. The trap wall portion 138A has an end surface facing the sliding surface 21 of the rotary seal ring 20 of the trap wall portion 138A and the land 12 are flush with each other.

Accordingly, in the trap portion 138, when the sealed liquid F flows into the liquid guide groove portion 158 from the atmosphere side to the sealed liquid F side, the outer diameter side end surface 19a of the convex portion 19 functions as a guide surface that guides the sealed liquid F toward the Rayleigh step 94A, so recovery of the sealed liquid F into the Rayleigh step 94A is less likely to be hindered.

In addition, when the sealed liquid F flows into the liquid guide groove 158 from the sealed liquid F side to the atmosphere side, the trap section 138 can collect the sealed liquid F by the inner diameter side end surface 19b of the convex section 19 as shown by the halftone dots, so that the function of retaining the sealed liquid F in the liquid guide groove section 158 can be enhanced.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions within the scope of the present invention are included in the present invention.

For example, in the above embodiments, mechanical seals for general industrial machines are used as sliding parts, but other mechanical seals for automobiles, water pumps, etc. may also be used. In addition, it is not limited to mechanical seals, and sliding parts other than mechanical seals, such as slide bearings, may be used.

Further, in the above-described embodiment, an example in which the dynamic pressure generating mechanism is provided only on the stationary seal ring has been described, but the dynamic pressure generating mechanism may be provided only on the rotary seal ring 20, or may be provided on both the stationary seal ring and the rotary seal ring.

Further, in the above-described embodiment, a plurality of dynamic pressure generating mechanisms having the same shape are provided in the sliding component, but a plurality of dynamic pressure generating mechanisms having different shapes may be provided. Also, the intervals and the number of the dynamic pressure generating mechanisms can be changed as appropriate.

Further, the trap portion may be configured by appropriately combining the trap portions of the above-described Examples 1, 4 to 11, and the configuration may be appropriately changed as long as it is configured to suppress leakage to the low pressure side.

Further, in the above-described embodiment, the mechanical seal is described as an outside type that seals the sealed liquid F that tends to leak from the inner diameter side to the outer diameter side of the sliding surface.

Further, although the sealed fluid side is the high pressure side and the leak side is the low pressure side, the sealed fluid side may be the low pressure side and the leak side may be the high pressure side, or the sealed fluid side and the leak side may have substantially the same pressure.

9A Rayleigh step (shallow groove)
9B Reverse Rayleigh step (shallow groove)
10 stationary seal ring (sliding part)
11 Sliding surface 13 Trap parts 13A, 13B Trap piece 13a Low pressure side wall surface (guiding surface)
14 dynamic pressure generating mechanism 15 liquid guide groove (deep groove)
15a opening 15b downstream side wall surface (inner surface)
15c upstream side wall surface (inner surface)
15d bottom (inner surface)
19a Outer diameter side end surface (guide surface)
20 Rotating seal ring (sliding part)
21 Sliding surface 30 Meandering grooves 91A to 94A Rayleigh step (shallow groove)
91B-94B reverse Rayleigh step (shallow groove)
131 to 138 trap portions 141 to 149 dynamic pressure generating mechanisms 151 to 158 liquid guiding groove portions (deep groove portions)

Claims (9)

An annular sliding component arranged at a relatively rotating portion of a rotating machine,
The sliding surface of the sliding component is provided with a plurality of dynamic pressure generating mechanisms, each of which is composed of a deep groove portion communicating with the leak side of the outer diameter side or the inner diameter side, and a shallow groove portion extending in the circumferential direction and communicating with the deep groove portion. The sliding component according to claim 1, wherein the deep groove portion communicates with the outer diameter side. 3. The sliding component according to claim 1 , wherein the trap portion is a trap piece extending from the inner surface of the deep groove portion. 4. The sliding component according to claim 1, wherein said trap portion has a guiding surface for guiding the fluid to be sealed toward said shallow groove portion. 5. The sliding component according to any one of claims 1 to 4 , wherein the trap portion is arranged at least nearer to the opening communicating with the leak side of the deep groove portion. The sliding component according to any one of claims 1 to 5 , wherein the trap portion is arranged at least at an intersection of the deep groove portion and the shallow groove portion. The sliding component according to any one of claims 1 to 6 , wherein the trap portions are arranged line-symmetrically with respect to a center line extending in the radial direction of the deep groove portion. The sliding component according to any one of claims 1 to 7 , wherein the trap portion is formed integrally with a base material forming the sliding surface. The sliding component according to any one of claims 1 to 8 , wherein the trap portion forms a meandering groove meandering in the deep groove portion.

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